<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>n级菜单栏</title>
	<link rel="stylesheet" type="text/css" href="index.css">
</head>
<body>
    <div id="box">
        <ul class="first">
            <li>一级菜单1
                <span>></span>
            </li>
            <li>一级菜单2
                <span>></span>
                <ul>
                    <li>二级菜单1
                        <span>></span>
                        <ul>
                            <li>三级菜单1
                                <span>></span>
                            </li>
                            <li>三级菜单2
                                <span>></span>
                            </li>
                            <li>三级菜单3
                                <span>></span>
                            </li>
                            <li>三级菜单4
                                <span>></span>
                            </li>
                        </ul>
                    </li>
                    <li>二级菜单2
                        <span>></span>
                        <ul>
                            <li>三级菜单4
                                <span>></span>
                            </li>
                            <li>三级菜单5
                                <span>></span>
                            </li>
                            <li>三级菜单6
                                <span>></span>
                            </li>
                            <li>三级菜单7
                                <span>></span>
                            </li>
                        </ul>
                    </li>
                    <li>二级菜单3
                        <span>></span>
                    </li>
                    <li>二级菜单4
                        <span>></span>
                        <ul>
                            <li>三级菜单8
                                <span>></span>
                            </li>
                            <li>三级菜单9
                                <span>></span>
                            </li>
                            <li>三级菜单10
                                <span>></span>
                            </li>
                            <li>三级菜单11
                                <span>></span>
                            </li>
                        </ul>
                    </li>
                </ul>
            </li>
            <li>一级菜单3
                <span>></span>
                <ul>
                    <li>二级菜单5
                        <span>></span>
                    </li>
                    <li>二级菜单6
                        <span>></span>
                        <ul>
                            <li>三级菜单12
                                <span>></span>
                            </li>
                            <li>三级菜单13
                                <span>></span>
                            </li>
                            <li>三级菜单14
                                <span>></span>
                            </li>
                        </ul>

                    </li>
                    <li>二级菜单7
                        <span>></span>
                        <ul>
                            <li>三级菜单15
                                <span>></span>
                            </li>
                            <li>三级菜单16
                                <span>></span>
                            </li>
                            <li>三级菜单17
                                <span>></span>
                            </li>
                            <li>三级菜单18
                                <span>></span>
                            </li>
                        </ul>
                    </li>
                    <li>二级菜单8
                        <span>></span>
                        <ul>
                            <li>三级菜单19
                                <span>></span>
                            </li>
                            <li>三级菜单20
                                <span>></span>
                            </li>
                            <li>三级菜单21
                                <span>></span>
                            </li>
                            <li>三级菜单22
                                <span>></span>
                            </li>
                        </ul>
                    </li>
                </ul>
            </li>
            <li>一级菜单4
                <span>></span>
            </li>
        </ul>
    </div>

	<script type="text/javascript" src="index.js"></script>
</body>
</html>